i have 15 platies and 30 guppy fry in 20 gallon . i found a white patch on one guppy so i add 1 table spoon salt per gallon slowly .according to me it was ick . so next day white patch has gone .keep salt for ten days and then slowly chage the water in 3 days . in spite of that my guppies are rubbing their bodies on gravel . and some of them remain surface of the aquarium with clamped fins. after adding salt my platies stop eating . they are not eating any thing i also use garlic in the feead egg yolk but they dont eat anything . some platies changed their colour some yellow or whitish cloudy . they standing in the corner of the aquarium or stay still in the bottom . and looking stress . now i seperate them but they are still same and not eating any thing . now i bought methylen blue for them . Can methylen blue cure the disease and how to use methylen blue .And how many days i should have to keep the medicine in the water . and the patch on guppy can be fungus or it was ick .

Thanks